hard drums

well i made my first ever drum loop on reason 4 using redrum and programmed it into the sequencer, but im having a little trouble getting it to sound "on time" in some parts it sound as if its just a millisecond out and ive been tweaking it about for ages and no success. so heres the sample, tell me what you think and how i could improve it. http://www.mediafire.com/?eyki3mwflnm

(shit, i didnt leave enogh room at the end for the reverb so it cuts out at the end)